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βγάζω κάνα φράγκο
However, the Greek expression does not imply high earnings; it just means "I make some money," usually not much.
The context would clarify the sum implied in "some."
For high earnings, the plural says it all: βγάζω φράγκα.
For clearly low earnings, there's βγάζω φραγκοδίφραγκα.